[SQL문제풀기] No Order Customers

문제

StrataScratch - No Order Customers

StrataScratch

https://platform.stratascratch.com/coding/10142-no-order-customers?code_type=3

내가 작성한 정답

MySQL, PostgreSQL

select first_name
from customers
where id not in (select distinct cust_id 
                 from orders
                 where order_date between '2019-02-01' and '2019-03-01')
order by 1;


select first_name
from customers
where id not in (select distinct cust_id 
                 from orders
                 where order_date between date'2019-02-01' and date'2019-03-01')
order by 1;

Oracle

-- 문자열 비교라 지양
select first_name
from customers
where id not in (select distinct cust_id 
                 from orders
                 where to_char(order_date,'yyyy-mm-dd') between '2019-02-01' and '2019-03-01')
order by 1;

-- 날짜로 바꿔서 비교 
select first_name
from customers
where id not in (select distinct cust_id 
                 from orders
                 where order_date between date'2019-02-01' and date'2019-03-01')
order by 1;